#include<stdio.h>
#include<math.h>
bool isprime(int n);

int main()
{
	int n;
	bool is;
	scanf("%d",&n);
	is = isprime(n);
	if(is)
		printf("%d is a prime number\n",n);
	else
		printf("%d is not a prime number\n",n);
}

bool isprime(int n)
{
	int i;
	if(n <= 1)	return false;
	
	for(i=2;i<sqrt(n);i++)
		if(n % i == 0) return false;
		
	return true;
}
